This is a tough one to guess without clues. So here goes: it is designed to break when needed. It has a couple of holes. The one in the picture is very young for one of these, as they would traditionally be used in very old mowers
. You may found the name being used in a generic sense and it has been used in other "machines." And clearly, you can make one yourself -- it is a wooden stick with a couple of holes on each end. Homer Simpson
would say it's a good stick for whacking snakes
. What do you think it is?